In the prior art, Japanese Patent Application Laid-Open No. 49-68752 discloses a clock which includes a luminescence element mounted on a time display hand and a power supply device provided in a central portion of rotation of the display hand for supplying power to the luminescence element. This power supply device is configured so that two lead wires connected with a luminescence diode mounted on the display hand are extended individually to two conductor discs mounted on a rotary shaft of the display hand, and fixed slide members are adapted to slide individually on the conductor discs.
Further, Japanese Utility Model Application Laid-Open No. 56-9083 discloses a configuration in which each of hour and minute hand pipes has two contact members mounted on the periphery thereof, and two contact members connected to a luminescence element mounted on each of hour and minute hands are adapted to connect with the corresponding contact members mounted on the periphery of the corresponding pipe.
According to the foregoing first prior art, although the disclosed idea can be implemented when power is to be supplied to one display hand, it needs an ample space in the axial direction where power is to be supplied to a plurality of hands such as those of the clock, thereby making the implementation difficult.
According to the foregoing second prior art, with an increasing number of hands to be supplied with power, the contact members mounted on the periphery of each pipe become like an increasing number of concentric layers, thereby the diameter of a central shaft portion is extended and the configuration becomes complicated. Further, since those contact members are extended from the inside of a timepiece movement, the conventional timepiece movement itself cannot be used, with the result being that the design itself of the timepiece movement must be changed.
Therefore, it is an object of the present invention to provide a power supply device for a hand with a luminescence element using a simplified configuration, where electric power can be successively supplied to one hand and to other hands disposed in an upper space of the one hand in superposed relation.